Photon Detector Readout Plan Zelimir Djurcic, Patrick De Lurgio, Gary Drake, Michael Oberling Argonne National Laboratory zdjurcic@anl.gov, drake@anl.gov DUNE Photon Detection Review, August 2-3 2016
Introduction • The Following Review Questions will be addressed: ✔ ✔ ✔ ✔ ✔ 2
Readout Philosophy • Initial PD Readout Electronics Requirements developed with idea to have extremely high-performance readout system -address a wide range of R&D issues -enable validation and refinement of the DUNE photon detector requirements Details on requirements given in the LBNE docdb-7605, “Working Draft of Photon Detection System Electronics Requirements”, N. Buchanan, Z. Djurcic, G. Drake, M. Johnson, B. Jones, J. Klein, J. Musser, S. Seibert. • These requirements incorporated to Silicon Photo-multiplier Signal Processor (SSP) prototype module 3
Overview of the SSP Module • The Silicon Photo-multiplier Signal Processor (SSP) prototype module: – High-speed waveform digitizer – Current sensitive, differential input amplifiers à Good noise performance over long cables – Each channel has a 14-bit, 150 MSPS ADC – Timing obtained using signal processing techniques on leading edge of SiPM signal (CFD) – 12 channels per module – Uses Artix FPGA for sig. proc. – Has NOvA Timing Interface – Uses 120VAC; On-board LV power – Has internal prog. SiPM bias (30V) – Trigger: self or external – Has Trigger Out signal – Deep data buffering – 13 μ sec – No dead-time (up to 30 KHz/ch) – Programmable DAQ interface ð 1U rack-mounted unit ð Completely self-contained: Plug & Play – USB & GbE communications ð No crates needed – Internal charge injection ð No external power supplies needed – Internal bias monitoring ð No processor needed on front-end 4
Block Diagram of SSP Module Power 120V 60Hz Inputs From SiPMs Input Outputs From NOvA Timing Master 5
Overview of the SSP Module 6
Summary of Current Performance Attributes § § ADC Resolution Multi-Hit Capable – – 66 nA (1pe ≈ 160 fC at 1E6 gain) Resolve two pulses separated by <100ns § Differential Signal Input as separate hits − § >60 db common mode rejection Detection of Triplet (late) photons § Charge Measurement Accuracy – Waveform storage up to 2048 samples per – Channel gains matched to 1% in a event per channel possible – module, 2% overall Deep buffers capture both prompt and late § Electronics Noise light – § Trigger Interface 2.2 ADC counts RMS @ pedestal. § – Charge Measurement Dynamic Two modes, External and Internal – External : Read out programmable range – window of samples upon receipt of 14 bits trigger. § Linearity – Internal : Firmware reads out – Integral: ≤ 1%; Diff: ≤ 1 count automatically, sensing edges based on § Calibrations firmware constant-fraction discriminator. – On-board charge injection, 1% caps, § SiPM Bias Control 14-bit DAC – 30V bias for individual channels, with § Timing Resolution/Accuracy voltage monitor read back – ~3 ns for single pe’s (4 samples) § Dead Time ð Assume that we want to retain (most of) this – No Dead Time up to 30k events/s @ performance going forward… ð A review of the required specs is needed 100 samples per event (per ch) 7
Current Status § (4) prototype units manufactured and assembled – Currently in use at: (2) IU, (1) CSU, and (1) Warwick § (12+) small production version units manufactured and assembled – 7 installed with 35t + 1 spare at DAB – (1) CSU, (1) LSU, (2) ANL – Also, (1) used as a platform for the Calibration Module § Firmware development performed with 35 ton – Full ADC waveforms can be read out; ADC data processing firmware is complete – Have implemented CF timing, peak measurement, & total charge calculations – USB & GbE communication interfaces fully functional – Control & monitoring firmware is in place, including SiPM bias control & monitoring – NOvA Timing interface fully functional § Tests of analog performance meet specifications – Measurements of front-end show <300mV of noise in amplifier – ADC tests show <3 counts of total noise (~0.3 pe) – Single pe timing resolution ~3 ns ð Can measure single pe’s over ~25 meters of cable � No cold electronics needed 8
Performance Tests (show performance over a short/long cable in small dewars, time-resolution etc => some of it shown in other talks) 9
Results from 35-Ton Detector • PDs were noisier than originally anticipated. – Amount of noise varies by channel. – Some of the noise is feeding in from TPC electronics • We see the PD trigger rate shoot up when the TPC is in a high-noise state. – Readout threshold was set to 2.2 PE or 3.3 PE (depending on readout mode) instead of the desired 0.5 PE. – One third of the channels were turned off or suppressed with higher thresholds because of excess noise. • On well-behaved channels, signals of a few PE can still be seen clearly. 10
Results from 35-Ton Detector • Photo-detector/APA noise tests performed at 35-ton • Photon-detector noise study is performed based on SSPs pedestal runs with the SSPs in the following cases: a) the TPC turned off b) the TPC turned on but not taking data; and c) the TPC turned on and operating; • Tests a)-c) are susceptibility tests, to see if the SSP is picking up noise from the TPC. - From a), observe noise of the SSP system with no TPC noise sources present. This is presumably the best noise performance that the SSP system can do, although there may be other noise sources that we pick up that make it worse than expected. - From b), observe the noise of the SSP system with the TPC powered but not reading out. Might be able to say something about the source of the noise from this. - From c), observe noise of SSP system with TPC powered and reading out. This should be the worst case. 11
Results from 35-Ton Detector FFTs: Waveforms: Case A) Shows that photon detector picks a noise from APA, A typical SSP channel shown but is not a significant source Case B) of noise on its own. Case C) 12
PD Electronics Activities & Plans • Recent Activities – Implement and support readout of the 35-Ton Detector @ FNAL – SiPM ganging studies – Signal cable selection & tests – Associated connector selection • Current Activities (this fiscal year) – Development of a prototype SSP with new connectors and cables – Tests with new SiPM mounting/ganging board • Next Steps: ProtoDUNE – Incorporate design changes to meet protoDUNE requirements • DAQ • Timing • Power • Photon-Detector Feedthrough (APA Interface) • Grounding and Shielding – Fabricate SSP modules for protoDUNE 13
ProtoDUNE-SP DAQ Overview ProtoDUNE-SP DAQ Overview Diagram, By K. Hennessy, dune docdb-1463 14
ProtoDUNE-SP DAQ Overview ProtoDUNE-SP DAQ Overview Diagram, By K. Hennessy, dune docdb-1463 15
ProtoDUNE-SP DAQ Overview DAQ interface to SSPs under discussion with DAQ group: • Pass trigger info to SSP, operating in self-triggering mode -Collect full waveforms for beam triggers -For muons collect either waveforms or header info only • In general, a decision on what type data to collect could be formed at either SSP or Board Reader level ProtoDUNE-SP DAQ Overview Diagram, By K. Hennessy, dune docdb-1463 16
Timing Interface • The SSP clock management logic allows the ADCs in the SSP to be clocked to the NOvA timing system (or provide an external clock to the front panel) • “DAQ to Cold Electronics Protocol and Timing for the ProtoDUNE TPC”, DUNE-doc-1394, under development. -different from NOvA System • New timing system would ideally use existing NOvA timing physical link at SSPs, but the protocol will change -will require modifications to the SSP firmware Overview of the proposed timing distribution system 17
Photon-Detector Feedthrough • BNL responsible for a mechanical portion of the feedthrough (flange, seal, strain relief) design. • ANL responsible for Printed Circuit Board (PCB) Feed-through for Photon-Detector. • 3D CAD model of the CE flange, key drawings, and the fabrication package of a prototype CE flange PCB exists. -ANL will provide BNL an initial PD flange board PCB connector layout with minimum connector spacing. -BNL will try to fit this layout to the existing CE flange design (14” CF), and iterate with ANL to get to the final PCB. -BNL will be responsible for the integration of the PCB into the flange and leak checking. • We have yet to define the electrical testing protocol. Example of CE flange/ feedthrough design 18
Grounding and Shielding Approach • Grounding and Shielding requirements: • Describe modified SSP cable connector/cable plant … • There will be no AC distribution on top of the protoDUNE cryostat. Any equipment located on the top should be run with DC voltage -Requires DC-DC modification to SSPs power supply -DC powered SSPs may be located on top of the detector close to the feedthroughs (-Other electrical interfaces described as well -want to include SiPM board schematics and drawings -etc.) 19
Next Steps (describe how/when design changes will be incorporated, tested) 20
Schedule of Activities at CERN • Schedule developed to address system testing, integration, installation, commissioning. • PD readout activities start with a vertical slice test at CERN in Dec16 – Jan17. 21
Schedule of Activities at CERN 22
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